Plastic material covered lamp with panel push-fit mounting means



ETAL

Nov. 16, 1965 P. WRIGHT PLASTIC MATERIAL COVERED LAMP WITH PANEL PUgljl l T MOUNTING MEANS June 27. 1960 PC 0 A WT M a. N w I T United States Patent 3,218,509 PLASTIC MATERIAL COVERED LAMP WITH PANEL PUSH-FIT MOUNTING MEANS Peter Wright and Sidney John Noyce, Luton. Airport,

Bedfordshire, England, assignors to Hunting Engineering Limited, Luton Airport, Bedfordshire, England, a British company Filed June 27, 1960, Ser. No. 38,879 Claims priority, application Great Britain, June 29, 1959,

4 Claims. (or. 313-312 The invention relates to electric lamp bulbs, valves, fuses or the like having at least one filament, fuse, electrode or the like element contained within a cavity in an envelope which is usually of glass.

In one of its aspects the invention provides an electric lamp bulb, valve, fuse or the like having a glass envelope and a casing or holder of a plastic material moulded around the envelope.

The plastic material may be transparent or translucent and it may, in either case, be coloured or plain. It may, for example, be one of the polystyrene, acrylic, polyethylene or nylon resinous compounds, cellulose acetate or methyl methacrylate.

The envelope may be substantially completely encased in the casing or holder, electric leads to the filament or other internal electric device being taken through the casing or holder.

In one construction according to the invention the casing has a cylindrical or frusto-conical portion for push fitting into a hole or socket in a panel or other member to which the lamp or the like is to be attached.

In another of its aspects the invention provides an electric lamp bulb, valve, fuse or the like comprising a unitary moulding in glass or plastic having a cylindrical or frustoconical shank, an enlarged head on one end thereof and an internal cavity, at least one filament, fuse, electrode or the like element sealed within the cavity and at least one contact pin projecting from the base of the shank opposite to the head and connected to the element.

The invention is particularly suited for application to so-called miniature electric lamp bulbs having a consumption of only a few watts (e.g. 28 volts 0.04 amps.) and commonly used as indicator lamps in the motor, aircraft and electronic industries and in the medical field for external and internal examinations.

Some specific embodiments of electric lamp bulbs according to the invention and a mould tool for their formation, are shown in the accompanying drawings in which:

FIGURE 1 shows a vertical section through a first embodiment of lamp;

FIGURE 2 shows an exterior view of a second embodiment of lamp;

FIGURE 3 shows a section on the line 33 of FIG- URE 2;

FIGURE 4 shows an exterior view of a third embodiment of lamp;

FIGURE 5 is a view in the direction of arrow 5 of FIGURE 4;

FIGURE 6 is a vertical section through a fourth embodiment of lamp;

FIGURE 7 is an exploded view of an assembly of a further embodiment of lamp; and

FIGURE 8 is a section through a mould tool.

Referring to the embodiment of lamp shown in FIG- URE l, the lamp has a glass envelope 11 of generally cylindrical shape and tapering at one end 12 almost to a point. The wire leads 13 and 14 from the filament are taken out through the sides of the taper portion and soldered to tags 15 to which the wires of the circuit in which the bulb is used may also later be soldered. The

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bulb is moulded into a casing 16 of transparent polystyrene of the kind known as Lustrex G.P. This casing completely surrounds the lamp bulb and leads except for the portions of the tags 15 to which the circuit wires are to be soldered, these portions projecting from the casing side by side. The casing has a cylindrical portion 17 which is coaxial with the glass envelope and contains the tapered portion thereof as well as about half the cylindrical portion of the envelope. At the other end the casing has an enlarged head 18 which is of frusto-conical form co-axial with the cylindrical portion of the casing and contains the remainder of the bulb envelope. There is a sharp step 19 between the two portions of the casing and the end of the head is flat.

In use, the cylindrical portion of the casing is simply pushed into a closely fitting hole in a panel or other member to hold the lamp in place without any special construction of lamp holder.

Referring now to FIGURES 2 and 3 of the drawings a construction for a 6 volt 0.36 watt electric lamp bulb is shown. A glass envelope 21 containing a filament 22 has wire leads 23 and 24 soldered to brass plugs 25. The envelope is moulded into a casing 27 of polystyrene or polyethene, which completely surrounds the envelope and from which the ends of the plugs 25 protrude. The casing 27 has a substantially cylindrical portion 28 coaxial to the envelope and a part-spherical head 29 which head has flutes 30. A pair of diametrically opposed circumferential grooves 31 are in the cylindrical portion 28 immediately adjacent the head 29. Said grooves form no part of the invention but resulted merely from the particular procedure followed in manufacturing the casing. A pair of diametrically-opposed axially-extending projections 33 are positioned at the other end of the cylindrical portion 28 to the head, in line with the grooves 31, whereby a bayonet-type attachment to a panel may be made.

FIGURES 4 and 5 show a 14 volt 0.75 watt bulb in which the terminals are formed by a pair of brass tags 35. One end 36 of the tags is formed part-cylindrical to embrace the outer wall of the glass envelope 37 and to be attached to the wire leads from the filament. The tags generally follow the contours of the envelope and have parallel end parts 38 protruding from the casing 39 to form the circuit connections.

FIGURE 6 shows a fourth embodiment of bulb in which the glass envelope 41 is held in one, smaller diameter, end of a generally cylindrical metal sleeve 42 which is also attached to one wire lead from the filament. The other wire lead is attached to a central terminal 43. The envelope and sleeve are moulded in a plastic casing 44 forming a continuation of the cylindrical metal sleeve and having an enlarged head 45. The plastic material also fills the sleeve, allowing the terminal 43 to protrude. In use the lamp is mounted to be held round the plastic continuation of the cylindrical sleeve, while the sleeve itself is connected in the electric circuit.

FIGURE 7 shows a further construction of lamp and the assembly for panel mounting. The lamp shown has an enlarged head 49, a cylindrical casing 50 and a pair of axially-extending projections 51 similar to those shown in the construction of FIGURES 2 and 3. The bulb filament is connected to brass tags 52 protruding from one end of the plastic casing. A rubber O-ring 54 is arranged to fit on the cylindrical casing and to seat against the fiat underside of the head 49. The panel 55 on which the lamp is to be mounted, has a hole drilled to allow the cylindrical casing 50 to pass therethrough, the hole having small extensions 56 for the passage of the projections 51. In mounting the lamp on the panel, the O-ring 54 is placed on the cylindrical casing against the underside of the head, the projections 51 are aligned with the hole extensions 56 and the cylindrical casing is passed through the panel until the O-ring is compressed between the panel and the head 49. The lamp is then rotated about its axis so that the projections 51 are no longer aligned with the hole extensions 56 and the lamp is maintained in posi tion with the O-ring under compression by the cooperation of the underside of the head, the panel and the projections 54. Circuit connections to the brass tags 52 are made by the use of the connectors 58, which have spring engagement with the tags 52. With this assembly the compression of the O-ring effectively seals the panel.

FIGURE 8 shows a mould tool suitable for moulding the plastic casing on the bulb envelope. The external terminals (e.g., the brass plugs 25 of FIGURES 2 and 3) of the bulb are inserted into the drillings 60 to be a tight fit therein and support the envelope within the cylindrical mould 61. Plastic moulding material is then injected through entry 62.

The invention is not limited to the constructional details shown in the specific embodiments above described. Any desired shape or form of lamp casing may be used. The assembly into a panel or other mount may be by means of spire clip type panel holders, the casing may be suitably shaped to be readily attached to the clip. Alternatively the lamp casing can be a plain cylinder secured in a panel by a compression ring or a tubular clip. The lamp filament may be manufactured directly in a plastic envelope.

The invention is suitable for use with any lamp whose operating temperature is not too high for the plastic material chosen. Clearly lamps of higher operating temperatures require plastic materials of higher melting point.

Neon lamps complete with dropping resistors and miniature panel fuses may be moulded as described herein. A lamp lens and bulb combined may also be moulded for example for use as a cycle front lamp.

We claim:

1. An electric lamp bulb comprising a glass envelope, an electrical element sealed within said envelope, a unitary moulded casing of plastic material substantially completely surrounding said envelope and comprising a holder portion generally of the shape of a figure of revolution and an enlarged head portion, there being a step at the junction between the head and the holder portions, and a pair of electrical leads projecting from one end of said holder portion and connected to the element sealed within the envelope whereby the said holder portion is push-fitted into a hole of a mounting means with said step abutting against said mounting means.

2. An electric lamp bulb as claimed in claim 1 in which the plastic material is polystyrene.

3. An electric lamp bulb as claimed in claim 1 in which the head portion is fluted to efiect diffusion of the light.

4. An electric lamp bulb comprising a glass envelope, an electrical element sealed within said envelope, a unitary moulded casing of plastic material substantially completely surrounding said envelope and comprising a holder portion generally of the shape of a figure of revolution and an enlarged head portion, there being a step at the junction between the head and the holder portions, and a pair of electrical leads projecting from one end of said holder portion and connected to the element sealed with in the envelope in combination with a throughway socket in a panel whereby the said holder portion is a push-fit within the socket and the step engages with the mouth of the socket, the head portion being on one side of the panel and the electrical leads on the other side.

References Cited by the Examiner UNITED STATES PATENTS 1,988,290 1/1935 Wright 313-271 1,995,863 3/1935 Prideaux 3 133 12 X 2,134,472 10/1938 Criger et al. 3l3-3l8 2,641,726 6/1953 Cisne 313317 X 2,892,992 6/1959 Grovemiller 313-318 X 2,904,617 9/1959 King 3133 12 X 2,969,479 1/1961 Lawson 3l3-3l8 X 2,983,838 5/1961 Pechy 3l3-318 2,999,180 9/1961 Howles et al 3 l3318 3,020,437 2/ 1962 Horan 313-318 3,027,481 3/1962 Babel et a1 313-318 X GEORGE N. WESTBY, Primary Examiner.

RALPH G. NILSON, Examiner. 

1. AN ELECTRIC LAMP BULB COMPRISING A GLASS ENVELOPE, AN ELECTRICAL ELEMENT SEALED WITHIN SAID ENVELOPE, A UNITARY MOULDED CASING OF PLASTIC MATERIAL SUBSTANTIALLY COMPLETELY SURROUNDING SAID ENVELOPE AND COMPRISING A HOLDER PORTION GENERALLY OF THE SHAPE OF A FIGURE OF REVOLUTION AND AN ENLARGED HEAD PORTION, THERE BEING A STEP AT THE JUNCTION BETWEEN THE HEAD AND THE HOLDER PORTIONS, AND A PAIR OF ELECTRICAL LEADS PROJECTING FROM ONE END OF SAID HOLDER PORTION AND CONNECTED TO THE ELEMENT SEALED WITHIN THE ENVELOPE WHEREBY THE SAID HOLDER PORTION IS PUSH-FITTED INTO A HOLE OF A MOUNTING MEANS WITH SAID STEP ABUTTING AGAINST SAID MOUNTING MEANS. 